#include <bits/stdc++.h>
using namespace std;

int main() {
	int t;
	cin >> t;
	for (int i = 0; i < t; ++i) {
		long n;
		cin >> n;
		long ans = (2 + 2 * n) * n / 2;
		cout << ans << endl;
		return 0;
	}

}